Polysilane compounds and electrophotographic photosensitive members with the use of said compounds

ABSTRACT

There are provided a new polysilane compound having a weight average molecular weight of 6000 to 200,000, having neither chlorine radical nor other radicals resulted from side reaction, and all the Si radicals of which not having any oxygen, and a process for the production thereof. 
     Said polysilane compound can be utilized in the preparation of various electronic devices, medical devices, etc., thus it is a high molecular substance which has a high industrial value in use. 
     There is also provided an electrophotographic photosensitive member having a light receiving layer containing said polysilane compound.

FIELD OF THE INVENTION

The present invention relates to a new polysilane compound and a processfor the production thereof. The present invention also relates to anelectrophotographic photosensitive member wherein an organic material isused. More particularly, the present invention relates to anelectrophotographic photosensitive member having a light receiving layerformed with the use of a new polysilane compound capable of providingimproved electrophotographic characteristics.

BACKGROUND OF THE INVENTION

In The Journal of American Chemical Society, 125, pp. 2291 (1924),polysilanes were reported to be insoluble in solvents. In recent years,since it was reported in The Journal of American Ceramic Society, 61,pp. 504 that polysilanes are soluble in solvents and films can be madeof them, the public attention has been focussed on polysilanes. JapaneseUnexamined Patent Publications Sho. 60(1985)-98431 and Sho.60(1985)-119550 disclose polysilanes which can be dissociated withultraviolet rays and utilization of them in resists. Further, PhysicalReview B 35, pp. 2818 (1987) discloses polysilanes havingphotosemiconductor characteristics in which carriers are mobile due tobonds of their principal chains. These polysilanes are expected to beusable also in electrophotographic photosensitive members. However, inorder that polysilane compounds be applicable in electronic materials,those polysilane compounds are required to be such that they are solublein solvents and capable of providing films which are not accompanied byminute defects and excel in homogeneity. The electronic materials shouldnot be accompanied by any minute defects and because of this, polysilanecompounds to be used in the preparation of such electronic materials arerequired to be high quality polysilane compounds, which can bestructurally defined also with respect to substituents and do not causeany abnormality upon film formation.

There have been various reports of the synthesis of polysilanecompounds. Those polysilane compounds are still reported to beproblematic in using them in electronic materials. In The Journal ofAmerican Chemical Society 94(11), pp. 3806 (1972) and Japanese PatentPublication Sho. 63(1988)-38033, there are disclosed low-molecularweight polysilane compounds in with all the Si radicals beingsubstituted by organic groups. Those described in the former literatureare of the structure in which the end group of dimethylsilane issubstituted by a methyl group. Those described in the latter literatureare of the structure in which the end group of dimethylsilane issubstituted by an alcoxy group. Any of them is 2 to 6 in degree ofpolymerization and does not exhibit characteristics as the polymer.Particularly in this respect, none of them has an ability of forming afilm as it is, and is therefore, not industrially applicable.High-molecular weight polysilane compounds of the structure in which allthe Si radicals are substituted by organic groups have been recentlyreported in Nikkei New Material, pp. 46, Aug. 15 of 1988. These aresynthesized through specific intermediates to cause reduction in theiryield and it is difficult to mass-produce these on the industrial scale.

In addition, methods of synthesizing polysilane compounds have beenreported by The Journal of Organometallic Chemistry, pp. 198 C27 (1980)and The Journal of Polymer Science, Polymer Chemistry Edition vol. 22,pp. 159-170(1984). However, any of these synthetic methods is directedonly to condensation reaction of the polysilane principal chain but doesnot touch upon the end groups. In any of these synthetic methods,unreacted chlorine radicals and by-products due to side reactions arecaused and it is difficult to stably obtain polysilane compounds asdesired.

Use of such polysilane compounds as described above as a photoconductivematerial has been proposed by U.S. Pat. No. 4,618,551, U.S. Pat. No.4,772,525 and Japanese Unexamined Patent Publication Sho.62(1987)-269964. However, in any of these cases, occurrence ofundesirable negative effects due to said unreacted chlorine radicals andsaid by-products caused by side reactions are considered.

In U.S. Pat. No. 4,618,551, the foregoing polysilane compounds are usedin electrophotographic photosensitive members and an extremely highvoltage of 1000 V is applied upon use of those photosensitive members,although a voltage of 500 to 800 V is applied in an ordinaryelectrophotographic copying machine.

It is considered that this is done in order to prevent occurrence ofspotted abnormal phenomena on images reproduced since defects due to thestructural defects of the polysilane compound will be caused in theelectrophotographic photosensitive member at an ordinary potential. InJapanese Unexamined Patent Publication Sho. 62(1987)-269964,electrophotographic photosensitive members are prepared by using theforegoing polysilane compounds and a photosensitivity is observed foreach of them. However, none of those electrophotographic photosensitivemembers is not sufficient in photosensitivity and is inferior to theknown selenium photosensitive member or the known organic photosensitivemember in any respect.

There are a number of unsolved problems for any of the known polysilanecompounds to be utilized in the electronic materials. Thus, anypolysilane compound which can be desirably used for industrial purposeshas not yet been realized.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a new polysilanecompound of a weight average molecular weight in the range of from 6000to 200,000 in which all the substitutional groups and end groups aresubstituted by specific organic groups and a method for the productionthereof.

Another object of the present invention is to provide said polysilanecompound which has a good solubility in solvents and has an excellentfilm-forming ability, and a method for the production thereof.

A further object of the present invention is to provide anelectrophotographic photosensitive member having a light receiving layerformed of an organic photoconductive material, which satisfies variousrequirements desired for an electrophotographic photosensitive member.

A further object of the present invention is to provide anelectrophotographic photosensitive member having a light receiving layerformed of a new polysilane compound, which excels in sensitivity anddurability.

A further object of the present invention is to provide anelectrophotographic photosensitive member having a light receiving layerformed of a new polysilane compound which has a good solubility insolvents and an excellent film-forming ability.

A further object of the present invention is to provide the foregoingpolysilane compound which is usable in the preparation of variouselectronic devices and medical devices, and a method for the productionof said compound.

The present invention is to attain the above objects and to provide anew polysilane compound having a weight average molecular weight in therange of from 6000 to 200,000 which is represented by the followingformula (I) a method for the production thereof. ##STR1## Wherein, R₁stands for an alkyl group of 1 to 2 carbon atoms; R₂ stands for an alkylgroup, cycloalkyl group, aryl group or aralkyl group of 3 to 8 carbonatoms; R₃ stands for an alkyl group of 1 to 4 carbon atoms; R₄ standsfor an alkyl group of 1 to 4 carbon atoms; A and A' respectively standsfor an alkyl group, cycloalkyl group, aryl group or aralkyl group of 4to 12 carbon atoms wherein the two substituents may be the same ordifferent one from the other; and each of n and m is a mole ratioshowing the proportion of the number of respective monomers versus thetotal of the monomers in the polymer wherein n+m=1, 0<n≦1 and 0≦m<1.

The polysilane compound according to the present invention which has aweight average molecular weight in the range of from 6000 to 200,000 andis expressed by the formula (I) has neither chlorine-containing groupnor side reaction--causing group in which all the Si radicals beingsubstituted by specific organic groups not containing any oxygen atom.The polysilane compound is not noxious, easily soluble in aromaticsolvents such as toluene, benzene, xylene, etc., halogenated solventssuch as dichloromethane, dichloroethane, chloroform, carbontetrachloride, etc., and other solvents such as tetrahydrofuran (THF),dioxane, etc., and has an excellent film-forming ability.

The film formed of the polysilane compound according to the presentinvention is homogenous, uniform in thickness, has an excellent heatresistance and excels in hardness and toughness.

The polysilane compound to be provided according to the presentinvention can be employed in the preparation of various electronicdevices, medical devices, etc., and thus it is a high molecular compoundof high industrial value in use.

The foregoing electronic device includes organic photoconductivemembers, electric conductive members, photoresists, light informationmemory elements, etc. The foregoing medical device includes artificialorgan, artificial blood vessel, transfusion bag, etc.

As described above, the polysilane compound to be provided according tothe present invention is represented by the foregoing formula (I) andhas a weight average molecular weight in the range of from 6000 to200,000. In a preferred embodiment in the viewpoints of desirablesolubility in solvents and desirable film-forming ability, thepolysilane compound has a weight average molecular weight preferably inthe range of from 8000 to 120,000, more preferably in the range of from10,000 to 80,000.

Polysilane compounds of less than 6000 in weight average molecularweight do not exhibit polymer characteristics and do not have afilm-forming ability. On the other hand, polysilane compounds exceeding200,000 in weight average molecular weight are poor with respect tosolubility in solvents, and it is difficult to form films therefrom.

In the case where a film especially excelling in toughness is desired tobe formed, it is desired to selectively use a polysilane compound of theforegoing formula (I) wherein the end groups A and A' are groupsselected from the group consisting of alkyl groups having 5 to 12 carbonatoms, cycloalkyl groups, aryl groups and aralkyl groups respectivelyhaving 5 to 12 carbon atoms. The most desirable polysilane compounds ofthe present invention in this case are those in which the end groups Aand A' are groups selected from the group consisting of alkyl groupshaving 5 to 12 carbon atoms and cycloalkyl groups having 5 to 12 carbonatoms.

Thus, the polysilane compound represented by the formula (I) can be usedfor various purposes. Especially, when it is used to form a lightreceiving layer of an electrophotographic photosensitive member, therecan be obtained a desirable electrophotographic photosensitive memberwhich exhibits excellent electrophotographic characteristics.

By the way, the known polysilane compounds are obtained respectively byusing dichlorosilane monomers as the starting materials, subjecting saidmonomers to dehaloganation with the use of a Na-catalyst andpolymerizing the resultants. Thus, they are mostly those that havehalogen radicals at their terminals.

For any of these known halogen radical-containing polysilane compounds,when it is used to form a light receiving layer of anelectrophotographic photosensitive member, the resultingelectrophotographic photosensitive member unavoidably becomes such thatis accompanied by the following problems and is not practically usable.That is, when the electrophotographic photosensitive member having alight receiving layer formed of such known halogen radical-containingpolysilane compound is engaged in the electrophotographic image-formingprocess, the halogen radicals will be traps for photocarriers tomobilize, to thereby unavoidably cause residual potential. And uponrepeatedly conducting charging and exposure, said residual potential isincreased and along with this, the potential in light is increased.Thus, said electrophotographic photosensitive member is poor indurability. Other than these problems, there are further problems forsaid electrophotographic photosensitive member. That is, when thehalogen radicals contained in the known polysilane compound constitutingthe photosensitive member are Cl radicals, the Cl radicals react withwater in the case where it is present, to generate hydrogen chloridegas. Said hydrogen chloride corrodes the conductive portion of thesubstrate of the electrophotographic photosensitive member having thelight receiving layer disposed on said conductive portion and saidconductive portion becomes non-conductive to cause defects on an imageto be reproduced.

However, as a result of examining an electrophotographic photosensitivemember prepared by using the foregoing polysilane compound of theformula (I) to form the light receiving layer thereof, the followingfacts have been found. That is, (a) said electrophotographicphotosensitive member has a high sensitivity and provides high qualitycopied images; (b) any undesirable trap is not caused, the residualpotential upon exposure is extremely small; (c) an excellent chargetransportation layer can be realized; and (d) when the foregoingpolysilane compound is used in combination with a charge generatingmaterial, an electrophotographic photosensitive member excelling in theelectrophotographic characteristics can be obtained as desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-section view illustrating the constitutionof an electrophotographic photosensitive member having a single-layeredlight receiving layer according to the present invention.

FIGS. 2 and 3 are schematic cross-section views respectivelyillustrating the constitution of an electrophotographic photosensitivemember having a multi-layered light receiving layer according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Synthesis of new polysilanecompounds according to the present invention and examples of saidpolysilane compounds

The foregoing new polysilane compound to be provided by the presentinvention can be synthesized in the following manner. That is, underhigh purity inactive atmosphere containing neither oxygen nor water,dichlorosilane monomer in a solvent is contacted with a condensationcatalyst comprising an alkaline metal to conduct dehalogenation andcondensation polymerization, to thereby synthesize an intermediatepolymer. The intermediate polymer thus obtained is separated fromunreacted monomer and is reacted with a selected halogenating organicreagent in the presence of a condensation catalyst comprising analkaline metal to condense an organic group to the terminals of theintermediate polymer, thereby obtaining the polysilane compound.

In the above synthesizing process, as any of the foregoingdichlorosilane monomer, intermediate polymer, halogenating organicreagent and alkaline metal condensation catalyst is highly reactive withoxygen and water, the foregoing polysilane compound of the presentinvention cannot be obtained under such atmosphere wherein oxygen and/orwater are present.

Therefore, the foregoing procedures of obtaining the polysilane compoundof the present invention is necessary to be carried out under theatmosphere containing neither oxygen nor water. Thus, due care is to betaken that all the reagents to be used and the reaction vessel to beused contain neither oxygen nor water and the reaction system is notincorporated with oxygen or/and water during the synthesizing process.Specifically, with respect to the reaction vessel to be used, it issubjected to vacuum suction and argon gas substitution in a blow box,whereby eliminating adsorption of water or/and oxygen in the inside ofsaid vessel.

As for the argon gas used in any case, it is necessary that argon gas isdehydrated by passing it through a silica gel column, oxygen is thenremoved therefrom by passing the dehydrated gas through a column chargedwith copper power which is maintained at 100° C. and the argon gas thustreated is used. Likewise, as for the dichlorosilane monomer, prior toits introduction into the reaction system, oxygen is removed therefromby subjecting it to vacuum distillation with the use of said treatedargon gas free of oxygen, and thereafter it is introduced into thereaction system.

The halogenating organic reagent to be used and the solvent to be usedare also treated to be free of oxygen in the same manner as in the abovecase of treating the dichlorosilane monomer and they are introduced intothe reaction system. As for the solvent, it is desired to be treatedsuch that after being subjected to vacuum distillation with the use ofthe foregoing argon gas, the solvent is further treated with metallicsodium to be completely free of water.

As the foregoing condensation catalyst, a wire-like shaped alkalinemetal or chipped alkaline metals are used. In order to obtain said wiredalkaline metal or chipped alkaline metals, the starting alkaline metalis wired or chipped in a paraffinic solvent free of oxygen and theresultant is used while take care not to cause oxidation thereof.

As the starting dichlorosilane monomer to be used for producing the newpolysilane compound of the foregoing formula (I) according to thepresent invention, there is selectively used a silane compoundrepresented by the formula: R₁ R₂ SiCl₂ which will be later detailed orin addition, also selectively used a silane compound represented by theformula: R₃ R₄ SiCl₂ which will be later detailed.

As the foregoing condensation catalyst, it is desired to use an alkalinemetal capable of causing dehalogenation and providing condensationreaction. Specific examples of such alkaline metal are lithium, sodiumand potassium, among these, lithium and sodium being the most preferred.

The foregoing halogenating organic reagent is used for the introductionof a substituent represented by the A and a substituent represented bythe A'. As such halogenating organic reagent, there is used a relevantcompound selected from the group consisting of halogenated-alkylcompounds, halogenated-cycloalkyl compounds, halogenated-aryl compoundsand halogenated-aralkyl compounds, that is, a relevant compound selectedfrom the compounds represented by the general formula: A--X and/or acompound selected from the compounds represented by the general formula:A'--X (wherein X is Cl or Br) which will be later shown.

As for the foregoing dichlorosilane monomer represented by the generalformula: R₁ R₂ SiCl₂ or the dichlorosilane monomer represented by thegeneral formula: R₃ R₄ SiCl₂ which is additionally used, they aredissolved in predetermined solvents and introduced into the reactionsystem. As such solvent, it is desirable to us nonpolar paraffinichydrocarbon solvents. Specific examples of such nonpolar solvent aren-hexane, n-octane, n-nonane, n-dodecane, cyclohexane, cyclooctane, etc.

The intermediate polymer synthesized is insoluble in any of thesesolvents and thus, it can be effectively separated from the unreacteddichlorosilane monomer.

At the time of reacting the intermediate polymer separated from theunreacted dichlorosilane monomer with the halogenating organic reagent,they are dissolved in the same solvent and they are reacted. In thiscase, there is desirably used an aromatic solvent such as benzene,toluene, xylene, etc. as said solvent.

In order to obtain a desired intermediate by condensating the foregoingdichlorosilane monomer with the use of the foregoing alkaline metalcatalyst, the polymerization degree of the resulting intermediatepolymer can be controlled as desired by properly adjusting the reactiontemperature and the reaction period of time. However, as for thereaction temperature, it is desired to be regulated in the range of from60° C. to 130° C.

A preferred embodiment of the method for producing the foregoing newpolysilane compound represented by the formula (I) according to thepresent invention is to be explained in the following.

That is, the method for producing said new polysilane compound accordingto the present invention comprises the steps of: (i) producing theintermediate polymer and (ii) introducing the substituents A and A' tothe terminals of said intermediate polymer.

The step (i) can be carried out as follows. That is, the inside of thereaction system of the reaction vessel is made substantially free ofoxygen and water, charged with argon gas and the gas pressure thereof ismaintained at a predetermined value. A paraffinic solvent free of oxygenand a condensation catalyst free of oxygen are introduced into thereaction system, and dichlorosilane monomer(s) free of oxygen isintroduced thereinto. The reactants thus introduced into the reactionsystem were heated to a predetermined temperature while mixing them tocause condensation of said monomer. In this case, the condensationdegree of said dichlorosilane monomer is controlled as desired byproperly regulating the reaction temperature and the reaction period oftime, to thereby obtain an intermediate polymer having a desiredpolymerization degree.

The reaction in this case is performed in the way as shown in thefollowing reaction formula (i), wherein the chlorine radicals of the twodichlorosilane monomers and the condensation catalyst are reacted tocause dechlorination reaction wherein the Si radicals are repeatedlycondensated and polymerized, whereby affording an intermediate polymer.##STR2##

The reaction procedures in the above are made such that the condensationcatalyst (alkaline metal) is firstly placed in the paraffinic solvent,into which the dichlorosilane monomers are dropwise introduced whilestrirring the reaction mixture and maintaining it at an elevatedtemperature. The polymerization degree of the resultant is confirmed bysampling the reaction liquid. The confirmation of the polymerization canbe simply conducted by observing the state of the sampled reactionliquid if a film can be formed or not therefrom. When condensationproceeds to form a polymer, said polymer becomes precipitated in theform of white solid in the reaction liquid. When such white solid isprecipitated as desired, the reaction liquid containing the white solidis cooled and decanted to separate the precipitate from the solvent.Thus, there is afforded an intermediate polymer. Then, the foregoingstep (ii) is carried out. That is, the intermediate polymer thusobtained is subjected to dechlorination condensation with the use of thehalogenating organic reagent and the condensation catalyst (alkalinemetal) to thereby substitute the end groups of said intermediate polymerby predetermined organic groups. The reaction in this case is performedin the way as shown in the following reaction formula (ii). ##STR3##

Specifically in this respect, the intermediate polymer obtained bycondensation of the dichlorosilane monomers is dissolved in the aromaticsolvent. Then, the foregoing condensation catalyst (alkaline metal) isadded to the solution, and the foregoing halogenating organic reagent isdropwise added at room temperature. Wherein said halogenating organicreagent is added in an excessive amount of 0.01 to 0.1 folds over theamount of the starting monomer in order to compete condensation reactionbetween the end groups of the polymer. The reaction mixture is graduallyheated, and it is stirred for an hour while maintaining a temperature of80° C. to 100° C. to thereby perform the reaction as desired.

After the reaction is completed, methanol is added in order to removethe alkaline metal as the catalyst. Then, the resulting polysilanecompound is extracted with toluene and purified by the use of a silicagel column. Thus, there is obtained an objective new polysilane compoundaccording to the present invention.

Specific Examples of the R₁ R₂ SiCl₂ and R₃ R₄ SiCl₂ ##STR4## SpecificExamples of the A--X and the A'--X ##STR5##

As the catalyst, alkaline metals are desirable.

There is used lithium, sodium or potassium as the alkaline metal. Theshape of the catalyst is desired to be of wired form or chipped formhaving a large surface area.

Specific Examples of the new polysilane compound according to thepresent invention ##STR6## Electrophotographic Photosensitive Membersaccording to the present invention

The electrophotographic photosensitive member of the present inventionbasically comprises an electroconductive substrate and a light receivinglayer disposed on said substrate, said light receiving layer containingthe foregoing polysilane compound (that is, a polysilane compoundselected from C-1 to C-43 compounds). (The term "light receiving layer"in the present invention is to mean inclusively all the layers disposedon the electroconductive substrate.)

The foregoing light receiving layer may be constituted by a single layeror a plurality of functionally partitioned layers.

FIG. 1 is a cross-section view schematically illustrating theconstitution of a typical example of the electrophotographicphotosensitive member having a single light receiving layer according tothe present invention.

In FIG. 1, numeral reference 101 stands for a electroconductivesubstrate and numeral reference 102 stands for a light receiving layercontaining the foregoing polysilane compound. In this case, the lightreceiving layer 102 corresponds to a so-called photosensitive layercontaining the foregoing polysilane compound [which is corresponding toa material contributing to transporting a charge (hereinafter referredto as "charge-transporting material")] and other material contributingto generating a charge (hereinafter referred to as "charge-generatingmaterial").

The electrophotographic photosensitive member of the type shown in FIG.1 may have an undercoat layer (not shown) having a barrier function andan adhesion function between the conductive substrate and thephotosensitive layer (light receiving layer 102) or a surface protectivelayer (not shown) capable of protecting the photosensitive layer (lightreceiving layer 102) on said photosensitive layer, respectively in casewhere necessary.

In the case of the electrophotographic photosensitive member of theconfiguration shown in FIG. 1, the photosensitive layer (that is thelight receiving layer 102) contains the charge-generating material andthe charge-transporting material (that is the foregoing polysilanecompound) with a quantitative ratio (the charge-generating material: thecharge-transporting material) preferably of 1:100 to 1:1, morepreferably of 1:20 to 1:3, in a state that the two materials areuniformly distributed in the entire layer region thereof. The layerthickness thereof is preferably 4 to 30 μm, more preferably 7 to 20 μm.

As the foregoing charge-generating material, known organiccharge-generating materials or known inorganic charge-generatingmaterials can be selectively used. Specific examples of such organiccharge-generating material are azo pigment, phthalocyanine pigment,anthanthrone pigment, quinone pigment, pyranthrone pigment, indigopigment, quinacridine pigment, pyrrium pigment, etc. Likewise, specificexamples of such inorganic charge-generating material are selenium,selenium-tellurium, selenium-arsenic, etc.

The formation of the photosensitive layer (that is the light receivinglayer 102) of the electrophotographic photosensitive member of the typeshown in FIG. 1 may be carried out in the following way. That is, acoating composition is first prepared by dispersing a predeterminedamount of the foregoing charge-generating material in a proper solventto obtain an emulsion, and dissolving a predetermined amount of thepolysilane compound (a polysilane compound selected from the groupconsisting of the foregoing C-1 to C-43 compounds) in the emulsionobtained. The coating composition obtained is applied onto the surfaceof an electroconductive substrate in an amount which provides apredetermined thickness for the layer resulted after dried by anappropriate coating means to thereby form a liquid coat on said surface,which is followed by drying and solidifying by a conventional means. Asthe solvent used in this case, there can be illustrated aromaticsolvents such as benzene, toluene, xylene, etc., halogenic solvents suchas dichloromethane, dichloroethane, chloroform, etc., and other thanthese, tetrahydrofuran, dioxane, etc.

As the foregoing coating means, there can be illustrated a wire barcoating method, a dip coating method, a doctor blade coating method, aspray coating method, a roll coating method, a bead coating method, aspin coating method, etc.

In the case where the foregoing undercoat layer is disposed in theelectrophotographic photosensitive member of the type shown in FIG. 1,its thickness is desired to be preferably in the range of from 4 to 30μm, more preferably in the range of from 7 to 20 μm.

The undercoat layer is formed of a relevant material selected from thegroup consisting of casein, polyvinylalcohol, nitrocellulose, polyamides(nylon 6, nylon 66, nylon 610, copolymerized nylon, alcoxymethylatednylon, etc.), polyurethane and aluminum oxide.

The formation of the undercoat layer may be carried out by dissolvingthe undercoat layer-forming material in a solvent to prepare a coatingliquid when said material is soluble in a solvent or dispersing theundercoat layer-forming material in a solution containing binder resinwhen said material is insoluble in a solvent, to thereby prepare acoating composition, and applying said coating liquid or said coatingcomposition onto the surface of the electroconductive substrate 101 toform a liquid coat on said surface, followed by drying and solidifyingin the same manner as in the case of forming the photosensitive layer.

In the case of disposing the foregoing surface protective layer in theelectrophotographic photosensitive member of the type shown in FIG. 1,its thickness is desired to be 0.1 to 5 μm. The surface protective layeris formed of a resin such as polycarbonate A, polycarbonate Z,polyacrylate, polyester, polymethylacrylate, etc. The surface protectivelayer may contain an appropriate additive such as resistance-controllingagent, antideteriorating agent, etc. The formation of the surfaceprotective layer may be carried out by dissolving the foregoing resin ina relevant solvent to prepare a coating liquid, and applying the coatingliquid onto the surface of the previously formed photosensitive layer toform a liquid coat on said surface, followed by drying and solidifyingin the same manner as in the case of forming of the photosensitivelayer.

In the case where the resistance-controlling agent or theanti-deteriorating agent is incorporated into the surface protectivelayer, such additive is uniformly dispersed in the foregoing coatingliquid for the formation of the surface protective layer and as a resultof this, the resulting surface protective layer will contain suchadditive.

The electrophotographic photosensitve member having a light receivinglayer comprising a plurality of functionally partitioned layersaccording to the present invention typically takes the configurationshown in FIG. 2 or the configuration shown in FIG. 3. Specifically, theelectrophotographic photosensitive member of the configuration shown inFIG. 2 according to the present invention has, on an electroconductivesubstrate 201, a charge-generating layer 202 containing acharge-generating material and a charge-transporting layer 203containing the foregoing polysilane compound being stacked in this orderfrom the side of said substrate 201.

The electrophotographic photosensitive member of the configuration shownin FIG. 3 according to the present invention has, on anelectroconductive substrate 301, a charge-transporting layer 302containing the foregoing polysilane compound and a charge-generatinglayer 303 containing a charge-generating material being stacked in thisorder from the side of said substrate 301.

Each of the electrophotographic photosensitive member having theconfiguration shown in FIG. 2 and the electrophotographic photosensitivemember having the configuration shown in FIG. 3 according to the presentinvention may have an undercoat layer (not shown) or/and a surfaceprotective layer (not shown) as well as the electrophotographicphotosensitive member having the configuration shown in FIG. 1.

That is, as for the undercoat layer, it is disposed between theelectroconductive substrate 201 and the charge-generating layer 202 inthe case of the electrophotographic photosensitive member having theconfiguration shown in FIG. 2. In the case of the electrophotographicphotosensitive member having the configuration shown in FIG. 3, it isdisposed between the electroconductive substrate 301 and thecharge-transporting layer 302.

And, as for the surface protective layer, it is disposed on thecharge-transporting layer 203 in the case of the electrophotographicphotosensitive member having the configuration shown in FIG. 2. In thecase of the electrophotographic photosensitive member having theconfiguration shown in FIG. 3, it is disposed on the charge-generatinglayer 303.

In the electrophotographic photosensitive members shown in FIG. 2 andFIG. 3 respectively having the charge-generating layer (202 or 303) andthe charge-transporting layer (203 or 302), the thickness of each of thetwo layers is one of the important factors in order for theseelectrophotographic photosensitive members to exhibit desiredelectrophotographic characteristics. That is, in the case of theelectrophotographic photosensitive member shown in FIG. 2, it is desiredthat the charge-generating layer 202 is made preferably 0.01 to 5 μmthick, more preferably 0.05 to 2 μm thick, and the charge-transportinglayer 203 is made preferably 4 to 30 μm thick, more preferably 9 to 20μm thick.

In the case of the electrophotographic photosensitive member, it isdesired that the charge-transporting layer 302 is made preferably 4 to30 μm thick, more preferably 7 to 20 μm thick, and the charge-generatinglayer 303 is made preferably 1 to 15 μm thick, more preferably 3 to 10μm thick.

In the case of disposing the undercoat layer in the electrophotographicphotosensitive member shown in FIG. 2 or FIG. 3, its thickness ispreferably 4 to 30 μm, more preferably 7 to 20 μm. Likewise, in the caseof disposing the surface protective layer, its thickness is preferably0.1 to 5 μm.

As the charge-generating material to be contained in thecharge-generating layer 202 or 303, known organic charge-generatingmaterials or known inorganic charge-generating materials can be used.Specific examples of such organic charge-generating material are azopigment, phthalocyanine pigment, anthanthrone pigment, quinone pigment,pyranthrone pigment, indigo pigment, quinacridone pigment, pyrriumpigment, etc. Likewise, specific examples of such inorganiccharge-generating material are selenium, selenium-tellurium, seleniumarsenic, etc.

The charge-generating layer 202 or 303 can be formed by a conventionalmethod of evaporating the foregoing charge-generating material or aconventional method of preparing a coating composition containing theforegoing charge-generating material, applying the coating composition,drying and solidifying the resulting liquid coat. Among these twomethod, the latter is the most desirable. In the latter method,distribution of the charge-generating material into a charge-generatinglayer to be formed in a desirable state can be easily attained. In adetailed embodiment of the latter method, a relevant dispersing mediumis provided, the foregoing charge-generating material is introducedtogether with said dispersing medium into a relevant solvent to preparea coating composition in which said charge-generating material beinguniformly dispersed, this coating composition is applied to form aliquid coat, and the liquid coat is dried and solidified, wherebyforming the charge generating layer 203 or 303.

Desirable examples of said dispersing medium can include so-calledbinder resins such as insulating resins, organic photoconductivepolymers, etc. Specific examples of such binder resin are polyvinylbutyral, polyvinyl benzal, polyacrylate, polycarbonate, polyester,phenoxy resin, cellulose resin, acryl resin, polyurethane, etc. Otherthan these, it is possible to use the foregoing polysilane compoundaccording to the present invention as the dispersing medium.

In any case, the amount of the dispersing medium to be used ispreferably 80% by weight or less, more preferably 40% by weight or lessrespectively in terms of the content (quantitative proportion) in thecharge-generating layer (202 or 303) finally formed.

And as the foregoing solvent, there is selectively used an appropriatesolvent in which the foregoing binder resin can be effectively dissolvedand the foregoing charge-generating material can be uniformly dispersedin the binder resin dissolved. Specific examples of such solvent areethers such as tetrahydrofuran, 1,4-dioxane, etc.: ketones such ascyclohexanone, methyl ethyl ketone, etc.: amides such asN,N-dimethylformamide, etc.: esters such as methyl acetate, ethylacetate, etc.: aromatic compounds such as toluene, xylene,chlorobenzene, etc.: alcohols such as methanol, ethanol, 2-propanol,etc.: and aromatic carbon halides such as chloroform, methylenechloride, dichloroethylene, carbon tetrachloride, trichloroethylene,etc.

In order to form a liquid coat by applying the foregoing coatingcomposition, a conventional coating method can be employed. As suchcoating method, there can be illustrated a wire bar coating method, adip coating method, a doctor blade coating method, a spray coatingmethod, a roll coating method, a bead coating method, a spin coatingmethod, etc.

In order to dry and solidify the liquid coat formed, a proper drying andsolidifying method such as a known air-drying method which does notdamage the charge-generating layer (202 or 303) to be formed.

The charge-transporting layer 203 or 302 containing the foregoingpolysilane compound can be formed in the same manner as in the case offorming the charge-generating layer (202 or 303). For example, it can beformed by dissolving in a solvent a polysilane compound selected fromthe foregoing compounds C-1 to C-43 with an amount of preferably 5 to30% by weight, more preferably 10 to 20% by weight versus the amount ofsaid solvent to prepare a coating composition, applying the coatingcomposition to form a liquid coat, and drying and solidifying the liquidcoat. As said solvent, there can be illustrated aromatic solvents suchas benzene, toluene, xylene, etc., and other than these,tetrahydrofuran, dioxane, etc. The application of said coatingcomposition and the drying and solidification of said liquid coat can becarried out in the same manner as in the case of forming thecharge-generating layer (202 or 303).

In the case of disposing the undercoat layer or/and the surfaceprotective layer in the electrophotographic photosensitive member havingthe configuration shown in FIG. 2 or in the electrophotographicphotosensitive member having the configuration shown in FIG. 3, any ofsuch layers can be formed in the same manner as previously described inthe case of the electrophotographic photosensitive member shown in FIG.1.

Explanation is to be made on the electroconductive substrate (101, 201,301) in each of the electrophotographic photosensitive members shown inFIG. 1, FIG. 2 and FIG. 3.

First as for the shape thereof, it may take any configuration such ascylindrical, belt-like or plate-like shape. As for the constituentmaterial thereof, it may be an electroconductive member or a membercomprising an insulating base member applied with electroconductivetreatment to one of the surfaces thereof on which a light receivinglayer is to be disposed.

Examples in the former case are metal members of aluminum, copper, zinc,etc., other than these, alloy members of aluminum alloy, stainlesssteel, etc.

As for the latter case, there can be mentioned plastic base members ofpolyethylene, polypropylene, polyvinylchloride,polyethyleneterephthalate, acryl resin, etc. whose surface being appliedwith a metal thin film by a conventional vacuum evaporation method, saidplastic base members whose surface being applied with electroconductiveparticles of titanium oxide, tin oxide, carbon black, silver by the useof a binder resin, and other members comprising impregnating-basemembers such as papers or plastic films which are impregnated with saidelectroconductive particles.

Other than these members, there can be used other members comprisingmetal base members whose surface being applied with saidelectroconductive particles by the use of a binder resin as theforegoing electroconductive substrate.

For any of the electrophotographic photosensitive members shown in FIGS.1 to 3, in the case of forming a successive constituent layer on thepreviously formed constituent layer, it is important to selectively usea solvent which does not melt the previously formed layer.

The electrophotographic photosensitive members of the present inventionabove explained can be used not only in various electrophotographiccopying machines but also in laser beam printers, CRT printers, LEDprinters, liquid crystal printers, and laser plate making.

EXAMPLES

The present invention will be described more specifically whilereferring to Examples, but the invention is not intended to limit thescope only to these examples.

In the following production examples and comparative productionexamples, as for the product obtained, the presence or absence of Clradical was firstly observed. The product in which the presence of Clradical was recognized was subjected to determination of the content ofCl radical. The measured content thereof was expressed by the milimolarequivalence number per 1000 g of the product.

In addition, as for the product obtained, whether it corresponds or notto a polysilane compound having a backbone chain comprising a Si--Sibonded long chain structure was observed by FT-IR and/or UV spectrum.Further in addition, the presence or absence of a side chain substituentto have been bonded was observed by FT-IR, or/and the proton in thesubstituent was observed by FT-NMR.

On the basis of the results obtained, the structure of the synthesizedproduct was determined.

The foregoing observation of the presence or absence of Cl radical wasperformed by using a full-automatic X-ray fluorescence analyzing system3080 (product by Rigakudenki Kohgyo Kabushiki Kaisha). Wherein, therewas provided trimethylchlorosilane (product by Chisso Kabushiki Kaisha)as a reference standard, five kinds of control solutions were preparedby diluting said reference standard with respective rates of dilution of1, 5, 10, 50 and 100 times, each of the control solutions was set to theabove X-ray fluorescence analyzing system to measure the amount of Clradical contained therein, and an analytical curve was obtained based onthe measured results.

As for the product to be observed, 1 g thereof was dissolved indehydrated toluene to obtain a specimen of 10 ml in a total amount, thiswas set to the above X-ray fluorescence analyzing system, and themeasured result was referred to the foregoing analytical curve to obtainthe amount of Cl radical.

The measurement by FT-IR was performed by preparing a KBr pellet of thespecimen to be observed and setting the resultant to a Nicolet FT-IR 750(product by Nicolet Japan Co., Ltd.).

The measurement by FT-NMR was performed by dissolving the specimen to beobserved in CDCl₃ and setting the resultant to a FT-NMR FX-9Q (productby JEOL, Ltd.).

Additionally, Pure & Applied Chemistry 54, No. 5, pp. 1041-1050 (1982)reports with respect to UV spectra that in the case of a low molecularweight polysilane compound, its UV spectrum ranges in the shortwavelength side and in the case of a high molecular weight polysilanecompound, its UV spectrum ranges in the long wavelength side.

EXAMPLE 1

A three-necked flask was placed in a blow box which was vacuum-aspiratedand charged with argon gas, and a reflux condenser, temperature gage anddropping funnel were provided to the device. And argon gas was passedthrough a by-pass pipe of the dropping funnel.

100 g of dehydrated dodecane and 0.3 moles of wire-like shaped metallicsodium were introduced into the three-necked flask and heated to 100° C.while stirring. Then, a solution prepared by dissolving 0.1 moles ofdichlorosilane monomer (product by Chisso Kabushiki Kaisha)(a-7) in 30 gof dehydrated dodecane was dropwise added to the reaction system.

After its addition being completed, the reactants were subjected tocondensation polymerization at 100° C. for an hour to precipitate whitesolids. Thereafter the resultant was cooled and the dodecane wasdecantated. 100 g of dehydrated toluene was added to dissolve the whitesolids, to which 0.01 moles of mettalic sodium was added. Then, asolution prepared by dissolving 0.01 moles of n-hexylchloride (productby Tokyokasei Kabushiki Kaisha)(b-3) in 10 ml of toluene was dropwiseand slowly added to the reaction system while stirring, followed byheating at 100° C. for an hour. After cooling, 50 ml of methanol wasdropwise and slowly added to treat excessive mettalic sodium. As aresult, there were formed a suspended phase and a toluene phase. Thetoluene phase was separated, subjected to vacuum concentration, andpurified by a chromatography using a silica gel column to obtain aproduct with the yield of 65%.

The product thus obtained was examined by the foregoing method ofmeasuring the content of Cl radical. As a result, there was not observedany content of Cl radical (That is, 0.00 milimolar equivalence in 1000 gof the specimen.). As for the foregoing product, its weight averagemolecular weight was measured by subjecting the specimen to THFdevelopment in accordance with the known GPC method. It was 75,000(wherein polystyrene was made to be the reference standard.).

Further, a KBr pellet of the foregoing product was prepared and it wasset to a Nicolet FT-IR 750 (product by Nicolet Japan Co., Ltd.) tothereby measure its FT-IR. Further in addition, a specimen of theforegoing product was dissolved in CDCl₂ and set to a FT-NMR FX-90Q(product by JEOL, Ltd.) to measure its FT-NMR. As a result, it was foundthat the product does not contain any of Si--Cl bond, Si--O--Si bond andSi--O--R bond at all and corresponds to a polysilane compound having theforegoing structural formula C-I.

The above results were collectively shown in Table 4.

EXAMPLE 2

A three-necked flask was placed in a blow box which was vacuum-aspiratedand charged with argon gas, and a reflux condenser, temperature gage anddropping funnel were provided to the device. Argon gas was passedthrough the by-pass pipe of the dropping funnel.

100 g of dehydrated dodecane and 0.3 moles of metallic lithium of 1 mmin size were introduced into the three-necked flask and heated to 100°C. while stirring. Then, a solution prepared by dissolving 0.1 moles ofdichlorosilane monomer (product by Chisso Kabushiki Kaisha)(a-7) in 30 gof dehydrated dodecane was dropwise and slowly added to the reactionsystem. After its addition being completed, the reactants were subjectedto condensation polymerization at 100° C. for an hour to precipitatewhite solids. The resultant was cooled and the dodecane was decantated.100 g of dehydrated toluene was added to dissolve the white solids, towhich 0.02 moles of metallic lithium was added. Then, a solutionprepared by dissolving 0.02 moles of chlorobenzene (product by TokyoKasei Kabushiki Kaisha)(b-5) in 10 ml of toluene was dropwise and slowlyadded to the reaction system while stirring, followed by heating at 100°C. for an hour. After cooling, 50 ml of methanol was dropwise and slowlyadded to treat excessive metallic lithium. As a result, there wereformed a suspended phase and a toluene phase. The toluene phase wasseparated, subjected to vacuum concentration, and purified by achromatography using a silica gel column to obtain a productcorresponding to a polysilane compound No. 2 (the structural formula:C-3). The yield was 72%, and its weight average molecular weight was92,000. The determined results were shown in Table 4.

EXAMPLE 3

A three-necked flask was placed in a blow box which was vacuum-aspiratedand charged with argon gas, and a reflux condenser, temperature gage anddropping funnel were provided to the device. Argon gas was passedthrough the by-pass pipe of the dropping funnel.

100 g of dehydrated n-hexane and 0.3 moles of metallic sodium of 1 mm insize were introduced into the three-necked flask and heated to 80° C.while stirring. Then, a solution prepared by dissolving 0.1 moles ofdichlorosilane monomer (product by Chisso Kabushiki Kaisha)(a-7) indehydrated n-hexane was dropwise and slowly added to the reactionsystem. After its addition being completed, the reactants were subjectedto condensation polymerization at 80° C. for 3 hours to precipitatewhite solids. The resultant was cooled and the n-hexane was decantated.100 g of dehydrated toluene was added to dissolve the white solids, towhich 0.01 moles of metallic sodium was added. Then, a solution preparedby dissolving 0.01 moles of benzylchloride (product by Tokyo KaseiKabushiki Kaisha)(b-12) in 10 ml of toluene was dropwise and slowlyadded to the reaction system while stirring, followed by heating at 80°C. for an hour. After cooling, 50 ml of methanol was dropwise and slowlyadded to treat excessive metallic sodium. As a result, there were formeda suspended phase and a toluene phase. The toluene phase was separated,subjected to vacuum concentration, and purified by a chromatographyusing a silica gel column to obtain a product corresponding to apolysilane compound No. 3 (the structural formula: C-4). The yield was61%, and its weight average molecular weight was 47,000. The determinedresults were shown in Table 4.

Further, as for this polysilane compound, there was not present any IRabsorption belonging to unreacted Si--Cl, or to Si--O--Si or Si--O--R ofby-products.

EXAMPLES 4 and 5

The synthesizing procedures of Example 3 were repeated, except thatdichlorosilane monomer and end group treating agents shown in Table 1were used, to thereby obtain a polysilane compound No. 4 (the structuralformula: C-6) and a polysilane compound No. 5 (the structural formula:C-2) with respective yields of 60% and 62%.

For any of these polysilane compounds, there was not present any IRabsorption belonging to unreacted Si--Cl, or to Si--O--Si or Si--O--R ofby-products.

The determined results were collectively shown in Table 4.

COMPARATIVE EXAMPLE 1

The synthesizing procedures of Example 3 were repeated, except thatneither the condensation using the dichlorosilane monomer (product byChisso Kabushiki Kaisha)(a-7) nor the end group treatment of the polymerwas performed, to obtain a polysilane compound No. D-1 having thestructural formula shown in Table 4. The yield was 60% and its weightaverage molecular weight was 46,000. The determined results were shownin Table 4.

As for this polysilane compound, there were observed IR spectrabelonging to unreacted Si--Cl for the end group and belonging toSi--O--R of a by-product.

EXAMPLES 6 to 10

Polymerization was performed in the same manner as in Example 3, exceptfor using a polysilane monomer shown in Table 2 and changing thereaction period as shown in Table 2. As the end group-treating agent, acompound shown in Table 2 was used. The product synthesized was purifiedin the same manner as in Example 3.

In this way, there were obtained polysilane compounds Nos. 6 to 10.

The yield, the weight average molecular weight, and the results by FT-IRand FT-NMR with respect to each of the polysilane compounds were asshown in Table 4.

For each of these polysilane compounds, there was not observed any IRabsorption belonging to anreacted Si--Cl, or belonging to Si--O--Si orSi--O--R of by-products.

COMPARATIVE EXAMPLE 2

The procedures of Example 6 were repeated, except that the reactionperiod of the dichlorosilane monomer was made 10 minutes, to therebyobtain a polysilane compound No D-2 shown in Table 4.

The yield, the weight average molecular weight, and the results by FT-IRand FT-NMR of the resultant polysilane compound were as shown in Table4.

For the polysilane compound, there was not observed any IR absorptionbelonging to unreacted Si--Cl, or belonging to Si--O--Si or Si--O--R ofby-products.

EXAMPLES 11 to 14

The procedures of Example 1 were repeated, except that dichlorosilanemonomers and end group-treating agents were selectively used, to therebyobtain polysilane compounds Nos. 11 to 14 shown in Table 4.

The yield, the weight average molecular weight, and the results by FT-IRand FT-NMR with respect to each of the resultant polysilane compoundswere as shown in Table 4.

The copolymerized ratio of the silane monomer in each case was obtainedby the number of protons in the NMR.

COMPARATIVE EXAMPLE 3

A three-necked flask was placed in a blow box which was vacuum-aspiratedand charged with argon gas, and a reflux condenser, temperature gage anddropping funnel were provided to the device. Argon gas was passedthrough the by-pass pipe of the dropping funnel.

100 g of dehydrated dodecane and 0.3 moles of wire-like shaped metallicsodium were introduced into the three-necked flask and heated to 100° C.while stirring. Then, a solution prepared by dissolving 0.1 moles ofdichlorosilane monomer (product by Chisso Kabushiki Kaisha) in 30 g ofdehydrated dodecane was dropwise and slowly added to the reactionsystem. After its addition being completed, the reactants were subjectedto condensation polymerization at 100° C. for an hour to precipitatewhite solids.

After cooling, 50 ml of methanol was dropwise and slowly added to treatexcessive metallic sodium. Then, the resultant was subjected tofiltration to thereby separate the white solids, which were repeatedlywashed with n-hexane and methanol, to thereby obtain a polysilanecompound No. D-3 shown in Table 4.

This polysilane compound was insoluble in organic solvents such astoluene, chloroform, THF, etc. Thus, its determination was performed byFT-IR. The results obtained were as shown in Table 4.

COMPARATIVE EXAMPLE 4

A three-necked flask was placed in a blow box which was vacuum-aspiratedand charged with argon gas, and a reflux condenser, temperature gage anddropping funnel were provided to the device. Argon gas was passedthrough the by-pass pipe of the dropping funnel.

100 g of dehydrated dodecane and 0.3 moles of wire-like shaped metallicsodium were introduced into the three-necked flask and heated to 100° C.while stirring. Then, a solution prepared by dissolving 0.1 moles ofdichlorosilane monomer (product by Chisso Kabushiki Kaisha) in 30 g ofdehydrated dodecane was dropwise and slowly added to the reactionsystem. After its addition being completed, the reactants were subjectedto condensation polymerization at 100° C. for an hour to precipitatewhite solids.

After cooling, 50 ml of methanol was dropwise and slowly added to treatexcessive metallic sodium. The resultant was subjected to filtration toobtain the white solids, which were repeatedly washed with n-hexane andmethanol to obtain a polysilane compound No. D-4 shown in Table 4.

This polysilane compound was insoluble in organic solvents such astoluene, chloroform, THF, etc. Thus, its determination was performed byFT-IR. The results obtained were as shown in Table 4.

APPLICATION EXAMPLES Application Example 1-1

In the following, there will be described an example wherein thepolysilane compound of the present invention is used as a resistmaterial.

Phenol novolak resin (AZ B50J: product by Shipray Co., Ltd.) was appliedonto a silicon substrate to form a coat of 2 μm in thickness by a spincoating method, which was followed by heating at 150° C. for 30 minutes.Then, a liquid obtained by dissolving 5 parts by weight of thepolysilane compound No. 1 obtained in Example 1 and 0.5 parts by weightof p-hydroquinone in toluene was applied to form a polysilane layer of0.3 μm in thickness by the spin coating method, which was baked at 90°C. for 30 minutes to prepare a composited resist layer. This wasirradiated with UV rays from a xenon lamp of 500 W through a quartz maskof 0.2 μm and 0.5 μm in line widths for 30 seconds. The resultant wasdeveloped by immersing it in a mixed solvent composed of toluene andisopropyl alcohol (with the quantitative ratio 1:5) for 30 seconds, andrinsed with ispropyl alcohol to thereby obtain a positive resist patternof 0.2 μm and 0.5 μm in line widths. This was then subjected to oxygenplasma etching to dry-etch the lower organic layer. There could beformed a resist pattern having a 0.2 μm line width and a 0.5 μm linewidth which is of an aspect ratio being more than 2.

The film-forming ability and the developing property of a resist patternwere evaluated with respect to this polysilane compound, and theevaluated results were shown in Table 5. Further, the polysilanecompound was dissolved in methane, and set to a spectrophotometer(U-3400, product by Hitachi, Ltd.) to measure its ultraviolet absorptionspectrum. The resultant maximum absorption wavelength (λ max) was shownin Table 5.

Application Examples 1-2 to 1-18

The procedures of Application Example 1-1 were repeated, except that thepolysilane compound was replaced by one of the polysilane compounds Nos.2 to 14 and D-1 to D-4, to form resist patterns, which were evaluated.

The evaluated results were shown in Table 5.

Application Example 2-1

There was prepared an electrophotographic photosensitive member of thetype shown in FIG. 2.

As the substrate 201, there was used an aluminum substrate of 10 cm×10cm in size and 50 μm in thickness. Firstly, a charge-generating layer202 was formed on the aluminum substrate in the following manner. Thatis, 10 parts by weight of chloroaluminumphthalocyanine and 5 parts byweight of polyvinyl butyral were dispersed in 90 parts by weight ofmethyl ethyl ketone in a ball mill to prepare a coating composition forthe charge-generating layer 202. The resultant coating composition wasapplied onto the surface of the aluminum substrate in an amount toprovide a 0.3 μm thickness when dried, to form a liquid coat thereon bymeans of a wire bar coater. The liquid coat was dried to form a 0.3 μmthick charge-generating layer 202. Then, 20% by weight of the polysilanecompound obtained in Example 1 (the polysilane compound No. 1 shown inTable 4) was dissolved in 80% by weight of toluene to prepare a coatingliquid for the formation of a charge-transporting layer 203. Theresultant coating liquid was applied onto the surface of the previouslyformed charge-generating layer in an amount to provide a 10 μm thicknesswhen dried by means of a wire bar coater to form a liquid coat thereon,which was followed by drying to form a 10 μm thick charge-transportinglayer 203. Thus, there was obtained an electrophotographicphotosensitive member (Sample No. 1). The resultant electrophotographicphotosensitive member sample was evaluated with respect to variousviewpoints.

That is, the electrophotographic photosensitive member was set to anelectro-static copying sheet test device Model SP-428 (product byKawaguchidenki Kabushiki Kaisha), and in the static system, it wasengaged in corona charging at -5 KV, after being kept in dark for 1sec., subjected to exposure with an illumination intensity of 2.5 lux tothereby observe its photosensitivity, further subjected to intensiveexposure (illumination intensity: 2.0 lux.sec.) and destaticized.

As for its charging property, the exposure quantity required forattenuating the potential (V₁) after 1 sec. since the corona charging toa 1/2 was measured.

In addition, there were observed an initial residual potential V^(o)_(SL) and a residual potential V_(SL) after the intensive exposure.

Further in addition, the electrophotographic photosensitive membersample was put on a cylinder for the photosensitive drum of a PPCcopying machine NP-150Z (product by CANON Kabushiki Kaisha), and theresultant was set to said copying machine to repeatedly conductimage-reproduction. And the resultant initial image and the resultantlast image after 500 shots were evaluated. The electrophotographicphotosensitive member sample on the cylinder for the photosensitive drumafter 500 image reproduction shots was taken out from the copyingmachine, said photosensitive member sample was removed from saidcylinder and it was set to the foregoing electro-static copying sheettest device Model SP 428 to observe its charging characteristics. And avariation (ΔV_(SL)) of the residual potential (V_(SL)) was measured.

The results were as shown in Table 6.

Application Examples 2-2 to 2-5

There were prepared four kinds of electrophotographic photosensitivemember samples of the type shown in FIG. 2 (Samples Nos. 2 to 5)respectively in the same manner as in the case of Application Example2-1, except for using one of the polysilane compounds obtained inExamples 2, 3, 4 and 5 (the polysilane compounds No. 2, 3, 4 and 5 shownin Table 4) for the formation of the charge-transporting layer in eachcase.

Each of the resultant photosensitive member samples was evaluated in thesame manner as in the case of Application Example 2-1.

The evaluated results obtained were as shown in Table 6.

Comparative Example 2-1

There was prepared an electrophotographic photosensitive member sampleof the type shown in FIG. 2 (Sample No. E-1) in the same manner as inthe case of Application Example 2-1, except for using the polysilanecompound obtained in Comparative Example 1 (the polysilane compound No.D-1 shown in Table 4) for the formation of the charge-transportinglayer.

The resultant photosensitive member sample was evaluated in the samemanner as in the case of Application Example 2-1. The evaluated resultsobtained were as shown in Table 6.

Application Examples 2-6 to 2-10

There were prepared five kinds of electrophotographic photosensitivemember samples of the type shown in FIG. 2 (Samples Nos. 6 to 10)respectively in the same manner as in the case Application Example 2-1,except for using one of the polysilane compounds obtained in Examples 6,7, 8, 9 and 10 (the polysilane compounds No. 6, 7, 8, 9 and 10 shown inTable 4) for the formation of the charge-transporting layer in eachcase.

Each of the resultant photosensitive member samples was evaluated in thesame manner as in the case of Application Example 2-1.

The evaluated results obtained were as shown in Table 6.

Comparative Example 2-2

An attempt was made to prepare an electrophotographic photosensitivemember sample of the type shown in FIG. 2 (Sample No. E-2). Theprocedures up to forming the charge-generating layer followedApplication Example 2-1. Then, the polysilane compound obtained inComparative Example 2 (the polysilane compound No. D-2 shown in Table 4)was dissolved in toluene to prepare a coating liquid for the formationof a charge-transporting layer 203. The coating liquid was applied ontothe surface of the previously formed charge-generating layer 202 in anamount to provide a thickness of 10 μm to form a liquid coat, which wasfollowed by drying. As a result, cracks were caused at the layer beingdried. Thus, there could not be obtained a practically acceptablephotosensitive member.

Application Examples 2-11 to 2-14

There were prepared four kinds of electrophotographic photosensitivemembers (Samples Nos. 11 to 14) of the type shown in FIG. 2.

As the substrate 201, there was used an aluminum substrate of 10 cm×10cm in size and 50 μm in thickness in each case.

The charge-generating layer 202 was formed as follows in each case. 10parts by weight of a diazo pigment represented by the under-mentionedformula (I) and 5 parts by weight of polyvinyl butyral were dispersedinto 90 parts by weight of methyl ethyl ketone in a ball mill to therebyprepare a coating composition. The coating composition was applied ontothe surface of the foregoing aluminum substrate in an amount to providea thickness of 0.2 μm when dried to form a liquid coat by means of awire bar coater, which was followed by drying to thereby form a 0.2 μmthick charge-generating layer 202. As for the formation of thecharge-transporting layer 203, the kind of a polysilane compound to beused was changed in each case. That is, there were used the polysilanecompounds obtained in Examples 11 to 14 (the polysilane compounds Nos.11 to 14 shown in Table 4). The formation of the charge-transportinglayer 203 using one of these polysilane compounds was carried out in thesame manner as in the case of Application Example 2-1. Each of theresultant photosensitive member samples was evaluated in the same manneras in the case of Application Example 2-1.

The evaluated results obtained were as shown in Table 6. ##STR7##

Comparative Example 2-3 and 2-4

Two kinds of electrophotographic photosensitive members (Samples Nos.E-3 and E-4) were tried to obtain by repeating the procedures ofApplication Example 2-1, except for using one of the polysilanecompounds obtained in Comparative Examples 3 and 4 (the polysilanecompounds Nos. D-3 and D-4 shown in Table 4) for the formation of thecharge-transporting layer. However, any of the polysilane compounds Nos.D-3 and D-4 was insoluble in the organic solvent intended to use and itwas impossible to obtain a practically applicable photosensitive member.

Application Examples 2-15 to 2-19

There were prepared five kinds of electrophotographic photosensitivemembers (Samples Nos. 15 to 19) of the type shown in FIG. 2.

As the substrate 201, there was used an aluminum substrate of 10 cm×10cm in size and 50 μm in thickness in each case.

The charge-generating layer 202 was formed as follows in each case. 10parts by weight of a diazo pigment represented by the under-mentionedformula (II) and 5 parts by weight of polycarbonate were dispersed into90 parts by weight of tetrahydrofuran in a ball mill to thereby preparea coating composition. The coating composition was applied onto thesurface of the foregoing aluminum substrate in an amount to provide athickness of 0.3 μm when dried to form a liquid coat by means of a wirebar coater, which was followed by drying to thereby form a 0.3 μm thickcharge-generating layer 202. As for the formation of thecharge-transporting layer 203, the kind of a polysilane compound to beused was changed in each case. That is, there were used the polysilanecompounds obtained in Examples 1 to 5 (the polysilane compounds Nos. 1to 5 shown in Table 4). The formation of the charge-transporting layer203 using one of these polysilane compounds was carried out in the samemanner as in the case of Application Example 2-1. Each of the resultantphotosensitive member samples was evaluated in the same manner as in thecase of Application Example 2-1.

The evaluated results obtained were as shown in Table 6. ##STR8##

Application Example 2-20

There was prepared an electrophotographic photosensitive member of thetype shown in FIG. 3 (Sample No. 20).

There was used an aluminum substrate of 10 cm×10 cm in size and 5 um inthickness as the substrate 301. Firstly, there was formed acharge-transporting layer 302 on the surface of said aluminum substrate.That is, 20 parts by weight of the polysilane compound obtained inExample 1 (the polysilane compound No. 1 shown in Table 4) was dissolvedin 80 parts by weight of toluene to prepare a coating liquid for theformation of charge-transporting layer 302. The coating liquid wasapplied onto the surface of said aluminum substrate in an amount toprovide a thickness of 10 μm to form a liquid coat by means of a wirebar coater, which was followed by drying to form a 10 μm thickcharge-transporting layer 302. Then, 5 parts by weight ofdibromoanthanthrone represented by the under-mentioned formula(III)(Hoechst Co., Ltd.) and 10 parts by weight of the foregoingpolysilane compound No. 1 were dispersed in 80 parts by weight oftoluene in a ball mill to prepare a coating composition for theformation of a charge-generating layer 303. The coating composition wasapplied onto the surface of the previously formed charge-transportinglayer 302 in an amount to provide a thickness of 3 μm to form a liquidcoat by means of a wire bar coater, which was followed by drying to forma 3 μm thick charge-generating layer 303. Thus, there was obtained anelectrophotographic photosensitive member (Sample No. 20). Theelectrophotographic photosensitive member sample obtained was evaluatedin the same manner as in the case of Application Example 2-1. Theevaluated results obtained were as shown in Table 6. ##STR9##

Comparative Example 2-5

There was prepared an electrophotographic photosensitive member of thetype shown in FIG. 3 (Sample No. E-5) by repeating the procedures ofApplication Example 2-20, except that the material for the formation ofthe charge-transporting layer 302 was replaced by the polysilanecompound obtained in Comparative Example 1 (the polysilane compound No.D-1 shown in Table 4). The electrophotographic photosensitive membersample obtained was evaluated in the same manner as in the case ofApplication Example 2-1.

The evaluated results obtained were as shown in Table 6.

Comparative Examples 2-6 to 2-20

The procedures of Application Example 20 were repeated, except that thepolysilane compound No. 1 was replaced by the foregoing polysilanecompound No. D-1 in the formation of the charge-generating layer 303, tothereby prepare an electrophotographic photosensitive member (Sample No.E-6). The electrophotographic photosensitive member sample obtained wasevaluated in the same manner as in the case of Application Example 2-1.The evaluated results obtained were as shown in Table 6.

Application Example 2-21

There was prepared electrophotographic photosensitive member of the typeshown in FIG. 1 (Sample No. 21).

There was used an aluminum substrate of 10 cm×10 cm in size and 5 μm inthickness as the substrate 101.

5 parts by weight of perylene (trade name: NOBOPERMRED BL, product byHoechst Co., Ltd.) having the following structural formula (IV) and 20parts by weight of the polysilane compound obtained in ProductionExample 14 (the polysilane compound No. 14 shown in Table 14) weredispersed into 75 parts by weight of toluene in a ball mill to prepare acoating composition. The coating composition was applied onto thesurface of said aluminum substrate in an amount to provide a thicknessof 12 μm when dried to form a liquid coat by means of a wire bar coater,which was followed by drying to form a 12 μm thick photosensitive layer102. Thus, there was prepared an electrophotographic photosensitivemember (Sample No. 21). The electrophotographic photosensitive membersample obtained was evaluated in the same manner as in the case ofApplication Example 2-1. The evaluated results obtained were as shown inTable 6.

Comparative Example 2-7

The procedures of Application Example 2-21 were repeated, except thatthe polysilane compound No. 14 was replaced by the foregoing polysilanecompound No. D-1, to thereby obtain an electrophotographicphotosensitive member (Sample No. E-7).

The electrophotographic photosensitive member sample obtained wasevaluated in the same manner as in the case of Application Example 2-1.The evaluated results obtained were as shown in Table 6.

                  TABLE 1                                                         ______________________________________                                                   dichlorosilane                                                                         terminal group                                                       monomer  treating agent                                            ______________________________________                                        Example 4    a-7 0.1 mole                                                                             b-8 0.01 mole                                         Example 5    a-7 0.1 mole                                                                             b-5 0.01 mole                                         Comparative  a-7 0.1 mole                                                                             --                                                    example 1                                                                     ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                                       dichlorosilane                                                 dichlorosilane condensation period                                                                         terminal group                                   monomer        (minute)      treating agent                                   ______________________________________                                        Example 6                                                                             a-13 0.1 mole                                                                            180           b-3 0.01 mole                                Example 7                                                                             a-13 0.1 mole                                                                            120           b-7 0.01 mole                                Example 8                                                                             a-13 0.1 mole                                                                            90            b-12 0.01 mole                               Example 9                                                                             a-13 0.1 mole                                                                            60            b-8 0.01 mole                                Example 10                                                                            a-13 0.1 mole                                                                            30            b-5 0.01 mole                                Compara-                                                                              a-13 0.1 mole                                                                            10            b-3 0.01 mole                                tive                                                                          example 2                                                                     ______________________________________                                    

                                      TABLE 3                                     __________________________________________________________________________                                   terminal group                                         dichlorosilane monomer treating agent                                 __________________________________________________________________________    Example 11                                                                            a-1       0.05 mole                                                                          a-7                                                                              0.05 mole                                                                          b-15                                                                             0.01 mole                                   Example 12                                                                            a-1       0.05 mole                                                                          a-7                                                                              0.05 mole                                                                          b-7                                                                              0.01 mole                                   Example 13                                                                            a-7       0.05 mole                                                                          a-19                                                                             0.05 mole                                                                          b-3                                                                              0.01 mole                                   Example 14                                                                            a-7       0.05 mole                                                                          a-19                                                                             0.05 mole                                                                          b-8                                                                              0.01 mole                                   Comparative                                                                           (CH.sub.3).sub.2 SiCl.sub.2                                                              0.1 mole                                                                          --      --                                             example 3                                                                     Comparative example 4                                                                  ##STR10##                                                                               0.1 mole                                                                          --      --                                             __________________________________________________________________________

    TABLE 4       formula      compound No.polysilane      ##STR11##      [%]yield M. W. Hδ [ppm]FT-NMR [cm.sup.-1      ] FT-IR in 1000 g)equivalent(millimolarCl radical               Example 1 1      ##STR12##      65 75,000      ##STR13##      ##STR14##      0.00      Example 2 2     ##STR15##      72 92,000      ##STR16##      ##STR17##      0.00      Example 3 3     ##STR18##      61 47,000      ##STR19##      ##STR20##      0.00      Example 4 4     ##STR21##      60 51,000      ##STR22##      ##STR23##      0.00      Example 5 5     ##STR24##      62 49,000      ##STR25##      ##STR26##      0.00  Comparativeexample 1 D-1      ##STR27##      60 46,000      ##STR28##      ##STR29##      38.0      Example 6 6     ##STR30##      58 120,000      ##STR31##      ##STR32##      0.00      Example 7 7     ##STR33##      61 72,000      ##STR34##      ##STR35##      0.00      Example 8 8     ##STR36##      72 69,000      ##STR37##      ##STR38##      0.00      Example 9 9     ##STR39##      45 46,000      ##STR40##      ##STR41##      0.00  Example 10 10      ##STR42##      50      8,000     ##STR43##      ##STR44##      0.00  ComparativeExample 2 D-2      ##STR45##      30      3,000     ##STR46##      ##STR47##      0.00  Example 11 11      ##STR48##      55 71,000      ##STR49##      ##STR50##      0.00  Example 12 12      ##STR51##      60 59,000      ##STR52##      ##STR53##      0.00  Example 13 13      ##STR54##      63 69,000      ##STR55##      ##STR56##      0.00  Example 14 14      ##STR57##      62 58,000      ##STR58##      ##STR59##      0.00  Comparativeexample 3 D-3      ##STR60##      30 -- -- SiCH.sub.32960,2880SiCl530SiOSi1110  Comparativeexample 4 D-4      ##STR61##      25 -- --      ##STR62##

                                      TABLE 5                                     __________________________________________________________________________    application                                                                         polysilane                                                                          solubility                                                                            film-forming resist    λ max                       example                                                                             No.   (toluene)                                                                             ability      development                                                                             [nm]                               __________________________________________________________________________    1-1   1     ◯                                                                         ⊚                                                                           ⊚                                                                        337                                1-2   2     ◯                                                                         ◯                                                                              ◯                                                                           337                                1-3   3     ◯                                                                         ◯                                                                              ◯                                                                           337                                1-4   4     ◯                                                                         ◯                                                                              ◯                                                                           337                                1-5   5     ◯                                                                         ⊚                                                                           ⊚                                                                        337                                1-6   D-1   ◯                                                                         ◯                                                                              x         337                                1-7   6     ◯                                                                         ⊚                                                                           ⊚                                                                        321                                1-8   7     ◯                                                                         ◯                                                                              ◯                                                                           321                                1-9   8     ◯                                                                         ◯                                                                              ◯                                                                           321                                1-10  9     ◯                                                                         ◯                                                                              ◯                                                                           321                                1-11  10    ◯                                                                         ◯                                                                              Δ   321                                1-12  D-2   ◯                                                                         x            x         321                                1-13  11    ◯                                                                         ⊚                                                                           ⊚                                                                        304                                1-14  12    ◯                                                                         ◯                                                                              ◯                                                                           304                                1-15  13    ◯                                                                         ⊚                                                                           ⊚                                                                        306                                1-16  14    ◯                                                                         ◯                                                                              ◯                                                                           306                                1-17  D-3   x       x            x         --                                 1-18  D-4   x       x            x         --                                 Notes       ◯ :                                                                 excellently                                                                         ⊚ :                                                              obtained a tough                                                                         ⊚ :                                                              no defect with                                           soluble film not accompanied                                                                       a line width                                           Δ:                                                                        soluble by any defect                                                                              of 0.2 μm                                           x:                                                                              not   ◯ :                                                                 obtained a practi-                                                                       ◯ :                                                                 no defect with                                           soluble cally acceptable                                                                           a line width                                                     film not accompanied                                                                       of 0.5 μm                                                     by any defect                                                                            Δ:                                                                        occurrence of                                                  Δ:                                                                        obtained a film                                                                            non-developed                                                    accompanied by                                                                             portion                                                          partial cracks                                                                           x:                                                                              impossible to                                                  x:                                                                              could not form a                                                                           develop                                                          film                                                    __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________                electrophoto-                                                                          No. of the                                                           graphic photo-                                                                         polysilane                                                           sensitive member                                                                       compound                                                                            E 1/2   V.sup.o.sub.SL **                                                                 ΔV.sub.SL ***                                                                initial                                       sample No.                                                                             used* [lux · second]                                                               [V] [V]  image                             __________________________________________________________________________    application example 2-1                                                                    1       1     1.0     0   -3   normal                            application example 2-2                                                                    2       2     1.1     0   -2   normal                            application example 2-3                                                                    3       3     1.1     -1  -3   normal                            application example 2-4                                                                    4       4     1.1     0   -3   normal                            application example 2-5                                                                    5       5     1.1     -1  -3   normal                            comparative example 2-1                                                                   E-1      D-1   1.7     -100                                                                              -50  occurrence                                                                    of white                                                                      dots                              application example 2-6                                                                    6       6     1.2     0   -3   normal                            application example 2-7                                                                    7       7     1.2     0   -1   normal                            application example 2-8                                                                    8       8     1.2     0   -2   normal                            application example 2-9                                                                    9       9     1.2     -1  -2   normal                            application example 2-10                                                                  10       10    1.3     -3  -5   normal                            comparative example 2-2                                                                   E-2      D-2   --      --  --   --                                application example 2-11                                                                  11       11    1.3     0   -2   normal                            application example 2-12                                                                  12       12    1.3     0   -2   normal                            application example 2-13                                                                  13       13    1.4     -2  -3   normal                            application example 2-14                                                                  14       14    1.4     -2  -5   normal                            comparative example 2-3                                                                   E-3      D-3   --      --  --   --                                comparative example 2-4                                                                   E-4      D-4   --      --  --   --                                application example 2-15                                                                  15       1     1.2     0   -2   normal                            application example 2-16                                                                  16       2     1.2     0   -2   normal                            application example 2-17                                                                  17       3     1.3     0   -3   normal                            application example 2-18                                                                  18       4     1.2     0   -3   normal                            application example 2-19                                                                  19       5     1.2     0   -2   normal                            application example 2-20                                                                  20       1     5.4     +10                                        comparative example 2-5                                                                   E-5      D-1   1.8     -90                                        comparative example 2-6                                                                   E-6      D-1   8.9     +150                                       application example 2-21                                                                  21       9     7.2     +12                                        comparative example 2-7                                                                   E-7      D-1   15.3    +180                                       __________________________________________________________________________     Note:                                                                         *No. of the polysilane compound shown in Table 4                              **initial residual potential                                                  ***change in the residual potential                                      

We claim:
 1. A polysilane compound (i) having a weight average molecularweight of 6000 to 200,000, (ii) free from chlorine-and oxygen-containinggroups, (iii) readily soluble in organic solvents and (iv) capable offorming films, said polysilane compound represented by the generalformula (I): ##STR63## wherein R₁ is an alkyl group of 1 or 2 carbonatoms, R₂ is an alkyl group, cycloalkyl group, aryl group or aralkylgroup of 3 to 8 carbon atoms, R₃ is an alkyl group of 1 to 4 carbonatoms, R₄ is an alkyl group of 1 to 4 carbon atoms, A and A' arerespectively an alkyl group, cycloalkyl group, aryl group or aralkylgroup of 4 to 12 carbon atoms wherein the two substituents may be thesame or different, n and m respectively stands for a ratio showing theproportion of the number of a respective monomer versus the total numberof a respective monomer versus the total number of the monomers in thepolymer wherein n+m=1, 0<n≦1 and 0≦m<1.
 2. A polysilane compoundaccording to claim 1 which has a weight average molecular weight of 8000to 120,000.
 3. A polysilane compound according to claim 1, wherein A andA' are respectively an alkyl group or cycloalkyl group of 5 to 12 carbonatoms.
 4. A process for producing a polysilane compound (i) having aweight average molecular weight of 6000 to 200,000, (ii) free fromchlorine-and oxygen-containing groups, (iii) readily soluble in organicsolvents and (iv) capable of forming films, said polysilane compoundrepresented by the general formula I: ##STR64## wherein, R₁ is an alkylgroup of 1 to 2 carbon atoms, R₂ is an alkyl group, cycloalkyl group,aryl group or aralkyl group of 3 to 8 carbon atoms, R₃ is an alkyl groupof 1 to 4 carbon atoms, R₄ is an alkyl group of 1 to 4 carbon atoms, Aand A' are respectively an alkyl group, cycloalkyl group, aryl group oraralkyl group of 4 to 12 carbon atoms wherein the two substituents maybe the same or different, n and m respectively stands for a ratioshowing the proportion of the number of a respective monomer versus thetotal number of the monomers in the polymer wherein n+m=1, 0<n≦1, and0≦m<1; said process comprises the steps of:(a) contacting dichlorosilanemonomer with a condensation catalyst comprising an alkaline metal toperform dehalogenation and condensation polymerization therebysynthesizing an intermediate polymer under high purity and inactiveatmosphere which is free of oxygen and water, (b) separating saidintermediate polymer synthesized in step (a) from unreacted monomer, and(c) reacting said separated intermediate polymer with a halogenatingorganic reagent selected from the group consisting of halogenated alkylcompounds, halogenated aryl compounds and halogenated aralkyl compounds,in the presence of a condensation catalyst comprising an alkaline metalto condense organic groups to the terminals of said intermediatepolymer.